# All files / src/chap07 StateEffect.js

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     import { useEffect, useState } from 'react';

    export default function StateEffect({ init }) {
      const [count, setCount] = useState(init);
      const [foo, setFoo] = useState('foo');

      // State 값(count)이 변경된 경우에만 로그를 표시한다.
      useEffect(() => {
        console.log(`count is ${count}.`);
      }, []);
      const handleClick = () => setCount(count + 1);

      return (
        <>
          {/* 버튼에 타임스탬프 값 반영 */}
          <button onClick={() => setFoo(Date.now())}>Foo ({foo})</button>
          <button onClick={handleClick}>카운트</button>
          <p>{count}번 클릭되었습니다.</p>
        </>
      );
    }